1. Field of the Invention
The present invention relates to a transportation system of a car-side primary magnet type including a rail of a magnetic metal material laid so as to extend along a traveling track, a power car equipped with driving magnet units adapted to be magnetically attracted to the rail for circulating movement and a trailing car or trailing cars coupled to the power car as occasion demands and capable of carrying passengers therein.
2. Description of the Prior Art
A conventional magnet-type transportation system of the so-called CTM (continuous transit system by magnet) type employs a method of fixedly arranging the driving magnet units on the ground side, that is, the method in which the ground side serves as the primary side. More specifically, in this case, a plurality of magnetic belt conveyor units, each having its own circulating speed and connected to a power source, such as an induction motor, and a power transfer mechanism, such as a reduction gear, are arranged at given intervals on the ground side in such a manner that the magnetic belt conveyor units are laterally or vertically arranged at given intervals in a broken-line configuration along the traveling track in curved and grade sections. The resulting ground-side magnetic belt conveyor line is provided with a speed pattern, including given acceleration/deceleration sections and constant speed sections by virtue of the preset circulating speeds of the magnetic belt conveyor units. A car, having an independently moving function including magnet means (electromagnets and/or permanent magnets) adapted to be magnetically attracted to the magnetic belts of the conveyor line through support means, guide wheels and supporting wheels, or a train composed of such cars, is arranged and runs along the line. Such a magnet-type transportation system is well known from, for example U.S. Pat. Nos. 4,197,934, No. 4,278,164, No. 4,289,227, etc. Also, the system has been put in practical use as "MITSUKOSHI PANORAMA LINER" at the EXPO'90 "International Exposition of Flowers and Green Leaves" held in Apr. 1990 in the city of Osaka, Japan.
The conventional magnet-type transportation system is so designed that the car is hauled for movement by the rolling of the supporting wheels over the traveling track surface due to the magnets on the car side being magnetically attracted to the magnetic belt conveyors. In this case, the rotating shafts of the magnetic belt conveyor units are used in their horizontal or vertical positions. In the curved sections the car is forcibly guided along the guide tracks which are separately laid down, in addition to the ordinary traveling track.
Also, in the case of a continuous moving path (moving side-walk) disclosed, for example, in Japanese Patent Application No. 13911/1988, the magnetic belts of ground-side magnetic belt conveyor units are composed of belts with magnets. Also, the previously mentioned cars are replaced with a plurality of footboard pedestals, which are individually provided with magnetic pieces adapted to be magnetically attracted to the magnet belts and connected with one another by elastic coupling mechanisms of relatively low flexibility. These pedestals are arranged so as to be movable over the traveling path by means of the supporting wheels.
The conventional magnet-type transportation system presupposes a mass transportation of the type in which the cars or pedestals successively arrive at equal intervals of time at the platform so that the plurality of magnetic belt conveyor units, having individually preset speeds, are arranged along the traveling track irrespective of the variations and volume of the traffic demand and the line, on the whole, is provided with the necessary acceleration and deceleration pattern and constant speed pattern. In this case, it is necessary to arrange so that even if the circulating movement of the magnetic belt conveyor units, constituting the ground-side driving source, stops or the electromagnets on the car or the like are deenergized, due to such an inconvenience as the interruption of service in any part, the cars or the pedestals are restarted at the point of fault upon the resumption of normal service. For this purpose, the magnetic belt conveyor line must be composed of the magnetic belt conveyor units arranged at given intervals as the primary means on the ground so that of the plurality of magnets (of the hybrid type using both electromagnets and permanent magnets) on +the car side, the required number of the magnets are always attracted to any of these magnetic belt conveyor units.
As a result, it can be said that up to the time when the actual traffic demand attains the mass transportation demand predicted at the time of the building, the number of the magnetic belt conveyor units is considered to be excessive, in view of the actual traffic demand, but are arranged on the magnetic belt conveyor line. Also, to circularly move the magnetic belt conveyor units on the whole line regularly causes excessive energy consumption and excessive noise, thus requiring considerable contrivances. Also, essentially, the magnetic belt conveyor units must be arranged in the central portion of the traveling track and, therefore, the traveling track requires a space for the arrangement of the conveyor units as well as the attendant motors, rotation transmission mechanisms, etc. Therefore, particularly in the case of an elevated type of track, the girders forming the traveling track must be of the open structure to ensure the required space. An attempt to ensure a sufficient strength against the load inevitably limits available space, thereby placing a limitation to the construction of the magnetic belt conveyor system which can be arranged within the available space.
The conventional magnet-type transportation system is disadvantageous in that the preset car traveling speed pattern is not variable and, therefore, any change of the traveling pattern, e.g., an increase or decrease of the platforms, a change in the traveling track design, a change in the length of the train or the like requires a change in the combination of the existing magnetic belt conveyor units or their replacement.
Also, while all the magnetic belt conveyor units on the line can be kept circulating regularly, in order to ensure the desired energy saving and reduce the occurrence of noise due to the circulating movement, it is necessary to add a system so that as for example, only the magnetic belt conveyor units in the "feeder section", where the car exits, and the adjacent "feeder section" in front thereof in the direction of travel, are circulated; this is shifted along with the traveling of the car.
Since the magnetic belt conveyor units are arranged in a broken-line configuration in each of the grade and curved sections, when the car is forcibly guided along the curve by its guide wheels, the magnets on the car side do not follow the broken line but are obliquely moved relative to the magnetic belt surfaces under the effect of a torsional force, corresponding to the angle of the broken line, so that depending on the circumstances, the magnets are returned to the original positions only when the magnetic belts get off in the width direction and get rid of the torsional force in the gap portion between them and the preceding magnetic belts. In this case, the guide wheels also forcibly guide the car along the curved traveling track and are, therefore, subjected to a torsional force. Thus, a contrivance is required for alleviating and eliminating the occurrence of fatigue rupture due to the repetition of these actions.
With the conventional magnet-type transportation system, when the car passes over adjoining magnetic belt conveyor units, which are different stepwise in circulating speed from each other, or during the acceleration or deceleration period, the car is accelerated or decelerated to the preset speed of the destination magnetic belt conveyor units with an attendant slip between the attracted surfaces of the car magnets and the magnetic belts of the magnetic belt conveyor units. In this case, an irregular speed oscillation phenomenon, tending to deteriorate the riding comfort is caused in the car. Therefore, is necessary to devise a counter measure such as the one disclosed in Japanese Patent Publication No. 23270/1983 in which the arranging interval between the magnetic belt conveyor units is preset in correlation with the spacing between the foremost magnet and the rearmost magnet of the car in such a manner that the rearward magnets of the car are separated from the magnetic belt conveyor units to which the magnets were previously attracted as soon as the forward magnets in the travel direction of the car completely pass over to the preceding adjoining magnetic belt conveyor units. This counter measure gives rise to an inconvenience of limiting the allowance for the designing of the line.
Also, in the conventional magnet-type transportation system, the divergence and convergence of the line are effected in a manner such as that disclosed, for example, in the previously mentioned three U.S. Pat. Nos. In other words, a pair of electromagnets, each having pole faces turned toward the right and left sides respectively, are mounted on the car side and magnetic belt conveyor units, having vertical rotary shafts, are arranged on the right and left side walls of a ground traveling track so as to correspond to the pole faces. Only one or the other of the pair of electromagnets is energized and selectively attracted to the magnetic belt surface of the corresponding magnetic belt conveyor units, thereby causing the car to proceed in the direction of one branching side. The energization of the other electromagnet similarly causes the car to proceed in the direction of the other branching side. In this case, however, at least the pair of electromagnets having the pole faces turned toward the right and left sides must be arranged on the car side and their energization and deenergization must be controlled for the selection of the desired branching direction, thus making it impossible to use permanent magnets. In addition, the pair of vertical-type magnetic belt conveyor units respectively facing the right and left sides must be arranged on the side walls of the traveling track at each of the divergent and convergent portions and, moreover, the broken-line arrangement is required between the adjoining magnetic belt conveyor units at each of the divergent and convergent portions, thus causing the occurence of a torsional force corresponding to the broken-line angle in the car magnets in the same manner as mentioned previously.